Solid-state imaging devices using a CMOS technique have been known. Among them, a passive-pixel-sensor (PPS) solid-state imaging device has been known. The PPS solid-state imaging device includes a light receiving unit in which PPS pixels, each having a photodiode that generates an amount of charge corresponding to intensity of incident light, are two-dimensionally arranged in a matrix of M rows and N columns. Each pixel accumulates the charge generated in the photodiode responsive to incident light and outputs a voltage value corresponding to the amount of accumulated charge as pixel data.
In general, M pixels in each column are connected to an integrating circuit through a readout line that is provided in association with the column. The voltage value output from the integrating circuit is held once and is sequentially output while being controlled by a shift register.
The PPS solid-state imaging device is used for various purposes. For example, the PPS solid-state imaging device is combined with a scintillator unit to form an X-ray flat panel and is used for medical or industrial purposes. Specifically, the PPS solid-state imaging device is used in, for example, an X-ray CT apparatus or a micro focus X-ray inspection apparatus.
During the manufacture of the PPS solid-state imaging device, in general, test probes are placed on terminal electrodes to check the operation of, for example, the light receiving unit, the integrating circuit, or the shift register. For example, Patent Literature 1 discloses a technique for improving the shape of a pad in order to bring the probes into contact with the pads (terminal electrodes) with high accuracy during the test of the solid-state imaging device. In addition, Patent Literature 2 discloses a method of determining whether each element is defective with a probe test, when a plurality of MOS solid-state imaging devices is formed on one semiconductor wafer.
Patent Literature 3 discloses a technique that injects charge into a photodiode of each pixel in the CMOS image sensor, thereby checking the function without emitting light.